Back to EveryPatent.com
United States Patent |
5,524,776
|
Hall
,   et al.
|
June 11, 1996
|
Low inclination push back storage rack system
Abstract
A low inclination push back storage rack system is described, the system
having a plurality of storage lanes, each storage lane being equipped with
one or more rectangular carriages to transport a pallet load from a front
loading position to a rear storage position. Each carriage is provided
with axles on which wheels having notches about their peripheral
circumference are mounted. The wheels are typically V groove wheels. The V
groove wheels of each carriage roll on parallel spaced apart rounded
elongated rods, the V groove wheels on one side of the carriage rolling on
one elongated rod, the V groove wheels on the other side of the carriage
rolling on another elongated rod. The carriages wheels are supported and
guided by the elongated rounded rods. The spaced apart parallel rounded
elongated rods are supported by spaced apart rod support members extending
from the front of the storage lane to the rear of the storage lane. The
rod support members may be various structural members such as I beams,
channels, and angles. These members are directly supported by the rack
framework. Systems are described having a plurality of carriages, these
systems having a configuration allowing the carriages to pass each other,
one below the other.
Inventors:
|
Hall; Roger W. (3045 Gloucester St., Lancaster, PA 17603);
Reiter; Harold J. (2791 Ironville Pike, Columbia, PA 17512);
Whalen; David W. (101 Nordick Dr., Lancaster, PA 17602)
|
Appl. No.:
|
169520 |
Filed:
|
December 17, 1993 |
Current U.S. Class: |
211/151; 211/59.2; 414/276; 414/286 |
Intern'l Class: |
A47F 005/00 |
Field of Search: |
211/151,59.2,162
414/276,286
|
References Cited
U.S. Patent Documents
2834475 | May., 1958 | Reich | 211/113.
|
4155462 | May., 1979 | Bendel | 211/151.
|
4341313 | Jul., 1982 | Doring | 211/151.
|
4462500 | Jul., 1984 | Konstant et al. | 211/151.
|
4613270 | Sep., 1986 | Konstant et al. | 414/276.
|
4678091 | Jul., 1987 | Konstant et al. | 211/191.
|
4687404 | Aug., 1987 | Seiz et al. | 414/276.
|
4715765 | Dec., 1987 | Agnoff | 414/276.
|
4759676 | Jul., 1988 | Hammond | 414/276.
|
4773546 | Sep., 1988 | Konstant | 211/151.
|
4915240 | Apr., 1990 | Konstant | 211/151.
|
4949852 | Aug., 1990 | Allen | 211/151.
|
4955489 | Sep., 1990 | Allen | 211/151.
|
4982851 | Jan., 1991 | Konstant | 211/151.
|
4988251 | Jan., 1991 | Kinney | 414/276.
|
5062535 | Nov., 1991 | Potter | 211/162.
|
5080241 | Jan., 1992 | Konstant | 211/151.
|
5117990 | Jun., 1992 | Krummell et al. | 211/151.
|
5137159 | Aug., 1992 | Collins et al. | 211/151.
|
5141118 | Aug., 1992 | Gay | 211/151.
|
5170896 | Dec., 1992 | Konstant | 211/151.
|
5178288 | Jan., 1993 | Werner et al. | 211/151.
|
5180069 | Jan., 1993 | Krummell et al. | 211/151.
|
5184738 | Feb., 1993 | Allen | 211/151.
|
5203464 | Apr., 1993 | Allen | 211/151.
|
5312004 | May., 1994 | Krummell et al. | 211/151.
|
5316157 | May., 1994 | Konstant | 211/151.
|
5328038 | Jul., 1994 | Allen | 211/151.
|
5348169 | Sep., 1994 | Allen | 211/151.
|
Primary Examiner: Gibson, Jr.; Robert W.
Attorney, Agent or Firm: Williams; Daniel
Claims
What is claimed is:
1. A low inclination push back storage rack system having a plurality of
storage lanes defined by a plurality of vertical columns supporting a
plurality of horizontal support members each of the storage lanes
comprising:
(a) a first and a second spaced apart elongated rod support member, each
rod support member extending from the front of the lane to the rear of the
lane, each of said rod support members fixed to the horizontal support
members;
(b) a first and a second spaced apart elongated rod, the first elongated
rod being fixed to the first rod support member, the second elongated rod
being fixed to the second rod support member, the elongated rods being
parallel and extending from the front of the lane to the rear of the lane;
(c) a carriage assembly having a carriage frame further comprising front
and rear members defining a front and rear end, first and second side
rails, a pallet receiving surface, a first pair of axles disposed
perpendicular to the side rails and positioned toward the front end of the
carriage frame, a second pair of axles disposed perpendicular to the side
rails and positioned toward the rear end of the carriage frame, a
plurality of wheels, each wheel being rotationally mounted on its
respective axle and each wheel having a concave notch extending around the
peripheral circumferential surface of the wheel, said wheels being in
contact with the elongated rods so that the concave notch of each wheel
rests on and is guided by the respective elongated rod of which that wheel
contacts.
2. The push back storage rack system of claim 1 wherein the wheels have V
grooves extending around the peripheral circumferential surface of the of
the wheel.
3. The push back storage rack system of claim 2 wherein the elongated rods
have a circular cross section.
4. The push back storage rack system of claim 2 wherein the elongated rods
have a half round cross section.
5. The push back storage rack system of claim 3 wherein the elongated rod
support members have two flanges, said flanges being permanently joined
together to form an angle member.
6. The push back storage rack system of claim 4 wherein the elongated rod
support members are angle members.
7. The push back storage rack system of claim 3 wherein the elongated rod
support members are I beams.
8. The push back storage rack system of claim 4 wherein the elongated rod
support members are I beams.
9. A push back storage rack system having a plurality of storage lanes
defined by a plurality of vertical columns supporting a plurality of
horizontal support members each of the storage lanes comprising:
(a) a first and a second spaced apart elongated rod support member, each
rod support member extending from the front of the lane to the rear of the
lane, each of said rod support members fixed to the horizontal support
members;
(b) a third and a fourth spaced apart elongated rod support member, the
third and fourth rod support members extending from the front of the lane
to the rear of the lane and being fixed to and supported by the vertical
columns;
(c) a first and a second spaced apart elongated rods, the first elongated
rod being fixed to the first rod support member, the second elongated rod
being fixed to the second rod support member, the elongated rods being
parallel and extending from the front of the lane to the rear of the lane;
(d) a third and fourth spaced apart elongated rods, the third elongated rod
being fixed to the third rod support member, the fourth elongated rod
being fixed to the fourth rod support members, the third and fourth
elongated rods being parallel and extending from the front of the lane to
the rear of the lane;
(e) a first and a second carriage assembly, each carriage assembly having a
carriage frame further comprising front and rear members defining a front
and rear end, first and second side rails, a pallet receiving surface, a
first pair of axles disposed perpendicular to the side rails and
positioned toward the front end of the carriage frame, a second pair of
axles disposed perpendicular to the side rails and positioned toward the
rear end of the carriage frame, a plurality of wheels, each wheel being
rotationally mounted on its respective axle and each wheel having a
concave notch extending around the peripheral circumferential surface of
the wheel, said wheels being positioned on the elongated rods so that the
concave notch of the wheels rests on and is guided by the corresponding
elongated rods on which its wheel rides, the wheels of the first carriage
assembly resting on and being guided by the first and second elongated
rods, the wheels of the second carriage assembly resting on and being
guided by the third and fourth elongated rods, the second carriage
assembly being arranged to pass over the first carriage assembly.
10. The push back storage rack system of claim 9 wherein the wheels have V
grooves extending around the peripheral circumferential surface of the
wheel.
11. The push back storage rack system of claim 10 wherein the elongated
rods have a circular cross section.
12. The push back storage rack system of claim 10 wherein the elongated
rods have a half round cross section.
13. The push back storage rack system of claim 11 wherein the elongated rod
support members are angle members.
14. The push back storage rack system of claim 12 wherein the elongated rod
support members are angle members.
15. A push back storage rack system having a plurality of storage lanes
defined by a plurality of vertical columns supporting a plurality of
horizontal support members each of the storage lanes comprising:
(a) a first and a second spaced apart rod support member, each rod support
member extending from the front of the lane to the rear of the lane, each
of said rod support members having a plurality of flanges and being
supported by the horizontal support members in that lane;
(b) a first pair of elongated rods, each of said first pair of rods being
affixed to a corresponding flange on a different rod support member, the
elongated rods being parallel and extending from the front of the lane to
the rear of the lane;
(c) a second pair of elongated rods, each of said second pair of rods being
affixed to a corresponding flange on a different rod support member, the
elongated rods being parallel and extending from the front of the lane to
the rear of the lane;
(d) a first carriage assembly having a carriage frame further comprising
front and rear members defining a front and rear end, first and second
side rails, a pallet receiving surface, a first pair of axles disposed
perpendicular to the side rails and positioned toward the front end of the
carriage frame, a second pair of axles disposed perpendicular to the side
rails and positioned toward the rear end of the carriage frame, a
plurality of wheels, each wheel being rotationally mounted on its
respective axle and each wheel having a concave notch extending around the
peripheral circumferential surface of the wheel, said wheels being
positioned on the elongated rods so that the concave notch of the wheels
rests on and is guided by the corresponding elongated rods on which the
wheel rides, the wheels of the first carriage assembly resting on and
being guided by the first pair of elongated rods;
(e) a second carriage assembly having a carriage frame further comprising
of front and rear members defining a front and rear end, a plurality of
side rails attached to and joining the front and rear members, a plurality
of extension members downwardly disposed from said side rails, a first
pair and a second pair of axles, each axle attached to and laterally
disposed outwardly from its respective said extension member, the first
pair of axles being positioned toward the front end of the carriage frame,
the second pair of axles being positioned toward the rear end of the
carriage frame, a plurality of wheels, each wheel being rotationally
mounted on its respective axle and each wheel having a concave notch
extending around the peripheral circumferential surface of the wheel, said
wheels being 6 positioned on the elongated rods so that the concave notch
of the wheels rests on and is guided by the corresponding elongated rods
on which its wheel rides, the wheels of the second carriage assembly
resting on and being guided by the second pair of elongated rods.
16. The push back storage rack system of claim 15 wherein the wheels have V
grooves extending around the peripheral circumferential surface of the
wheel.
17. The push back storage rack system of claim 16 wherein the elongated
rods have a circular cross section.
18. The push back storage rack system of claim 16 wherein the elongated
rods have a half round cross section.
19. The push back storage rack system of claim 17 wherein the elongated rod
support members are I beams.
20. The push back storage rack system of claim 18 wherein the elongated rod
support members are I beams.
Description
BACKGROUND
Storage rack systems maximize the amount of goods that can be stored in a
given floor space. The simplest systems are racks with a plurality of
storage lanes placed in a horizontal and vertical array such that each
lane can be loaded or unloaded with a forklift from a front aisle. A
simple one deep system, open in the front, can be placed against a wall. A
front aisle permits a forklift front access to each lane. Although this
type of system may conserve floor space by providing additional vertical
storage, the aisles used by the maneuvering forklifts consume a great deal
of floor space.
Systems capable of storing multiple pallet loads, one behind the other, in
the lane further conserve floor space. Rollerways on the lower surface of
each lane allows pallets to be sequentially loaded and pushed to rear
storage positions in three or more deep systems. Declined rollerways allow
the rack systems to be loaded from the front; the pallet loads moving to
the rear under the force of gravity. The pallet loads are unloaded from
the rear of the rack in a first in-first out basis.
Deep rack, first in-last out, rollerway systems are designed having only
front access. The racks are pitched slightly upward so that the pallets
return to the loading position under the force of gravity.
However, rollerway storage systems presented problems because loads for
storage were customarily contained on wooden pallets. Broken or otherwise
defective wooden pallets would jam the rack system necessitating time
consuming and expensive hand unloading of the pallet before the rack
system was again functional. Moreover, rollerway storage systems were
expensive because of the large number of wheels required with each system.
Push back systems are first in-last out systems which employ moving
carriages on which loaded pallets are transported to rearward positions to
be temporarily stored. The carriages are mounted on flanged wheels which
run along parallel tracks that extend from the front to the rear of the
storage lane. The tracks are often structural members such as I beams or
channels. The wheel flange provides guidance along an edge of the track;
the wheel is supported on a flat portion of the structural member. Since
the tracks are structural members, the tracks also support and give
rigidity to the storage rack system.
Another push back system has the carriages mounted on flat wheels that have
the flat roller portion of the wheel at a slight angle off horizontal.
This angle mates with a corresponding angle on the structural member,
however carriage support is still provided by flat wheels rolling on a
flat surface.
Carriages in the pushed back positions were initially urged to return to
the front loading position by resilient means. However, it was found that
the carriages would return to the front loading position under the force
of gravity if the tracks were inclined toward the front loading position.
Use of flanged and flat wheels which ride on structural members causes
numerous secondary problems. First, dirt and debris can build up on the
track making it necessary to periodically clean the tracks. The debris
lays on the flat track and can jam the carriage similar to putting a wedge
under the wheel.
Secondly, the tracks must be carefully aligned. If they are too far apart,
the carriage may become cocked and jammed. If they are too close together,
flanged wheels will jam against the sides of the tracks and flat wheels
will jam against the sides of the structural members.
Thirdly, the track inclination must be greater than 3/8" per foot of
carriage run. This is necessary because of the large frictional forces
between the flanged wheels and the tracks. This large inclination angle
causes problems when varying weight loads are placed on the carriages.
Carriages with heavier loads return to the front position very rapidly,
necessitating a shock absorbing bumper to stop the carriages. Lightly
loaded carriages return very slowly or get hung up on track debris.
Finally, a large track inclination or pitch necessarily increases the
height of each storage lane. As systems become deeper and more vertical
lanes are involved, considerable vertical space is consumed because of
excessive track pitch.
In view of the aforementioned difficulties, it is an object of this
invention to provide a push back carriage system capable of being used
with a degree of track inclination less than 1/4 of an inch per foot.
Another object of this invention is to provide a push back storage rack
system that reduces sliding friction between the wheels and tracks thus
providing smooth flow at a low pitch or track inclination.
It is also an object of this invention to provide a push back carriage
system that is less susceptible to fouling with dirt and debris.
A further object of this invention is to provide a system in which the
track spacing tolerances are more generous so that carriages will not jam
between the tracks if the tracks are not perfectly parallel and separated
by a precisely correct distance.
It is yet another object of this invention to provide a push back system
that can be easily retrofitted into existing rack systems by retaining the
structural shell of the already existing rack system.
For the foregoing reasons, there is a need for an easily manufactured push
back rack storage system that is tolerant of less precise manufacturing
standards and yet capable of trouble free operation in dirty environments
and that provides easy smooth flowing carriages with minimal vertical
height loss.
SUMMARY OF THE INVENTION
The present invention relates to pallet rack storage systems that include a
moveable carriage. More particularly, the invention relates to storage
systems that employ a moveable carriage for loading, positioning, and
storing pallet loads in each lane of a push back storage rack. The
moveable carriage is mounted on shoulder bolts or stub axles about which V
groove wheels turn. The V groove wheels are supported on and guided by
elongated rounded rods extending from a loading position in the storage
rack to a storage position in the rack. The elongated rounded rods are
supported along their length by conventional hot rolled steel structural
members.
This low inclination push back storage rack system may be expanded to
permit a plurality of nesting carriages to move on a plurality of rods in
a fore and aft direction within a single lane and yet still maintain
simplicity of construction and ease of maintenance.
The skeleton of this low inclination push back storage rack system is
conventionally framed with main vertical support members extending
vertically from a base datum, the base datum usually being the floor of
the building. At the front of each lane, a front horizontal structural
member is fixedly attached between a pair of front vertical columns.
Additional horizontal structural members are supported by more rearwardly
positioned pairs of vertical columns. The horizontal structural members
define the base of a rearwardly extending lane. Each lane may be two or
more pallet loads in depth.
As viewed from the front of the lane, the transverse horizontal members are
fixed at progressively higher distances from the base datum so that the
more rearward transverse horizontal members in each lane are higher than
the more forward transverse horizontal members. All horizontal members in
each lane, except the front horizontal member, are aligned so as to define
a plane with a slight downward inclination toward the front of the lane.
Diagonal members connect the main vertical support members to give racking
strength to the push back storage rack.
Fixed to the horizontal members are a pair of parallel rearwardly extending
rod support members. Each rod support member is positioned contiguous to
the side of the rearwardly extending lane so that each lane has two
parallel rearwardly extending rod support members separated by a distance
that corresponds to the approximate width of the moveable carriages. The
rod support members are attached to and supported by the transverse
horizontal members. The rod support members are structural members which
support the weight of the movable carriages.
Moveable rectangular carriages support the pallet loads that are loaded
from the front of the lane. Shoulder bolts are mounted on the side members
of each moveable carriage where the wheels are to be positioned. V groove
wheels are mounted on and rotate around the axis of the shoulder bolts,
however, sufficient clearance is provided on either side of the wheel to
allow the wheels to laterally drift along the axis of the shoulder bolts.
The V grooves in the wheels mate with the rearwardly extending elongated
parallel rods. Thus, each carriage is supported and guided by its V groove
wheels riding on their corresponding and respective rearwardly extending
elongated parallel rods. Contact between the V groove in each wheel with
its respective supporting rod is at only two points.
This wheel system is self cleaning because the wheels are not rolling on a
flat horizontal surface on which debris may easily collect. In this
V-groove wheel system, debris slips off the curved upper surfaces of the
rods onto the flat surfaces of the rod support members. Debris does not
interfere with wheel movement until there is a significant build up of
debris on the rod support members.
Another advantage of this low inclination push back storage rack system is
that the self cleaning feature allows the carriages to roll freely and
uniformly as long as the build up of debris does not rise to the level of
the rods. In a conventional flat wheeled system, any debris on the track
can cause an impediment to the rolling motion of the carriages.
Yet another advantage of the present invention is that, if the elongated
rods are not perfectly parallel, the wheels do not bind on the tracks or
rods. Instead, the wheels drift laterally on their respective shoulder
bolts thus compensating for alignment deviations between the rods
supporting the carriage.
Still another advantage of this system are the low frictional losses
provided by the two point contact between the wheel and the rod. This two
point contact allows the inclination of the rods to be kept to less than
1/4 of an inch per foot, even for lightly loaded carriages. Flat flanged
wheels require substantially greater track inclinations to compensate for
their higher frictional losses and obstacles caused by minor debris
accumulations.
Yet another advantage of this push back system is that the height of each
storage lane may be reduced because of the lower track or rod pitch that
is used with this low inclination system.
The foregoing advantages of this invention satisfies the need for a low
inclination, low height, low friction, push back storage rack system that
has wide manufacturing tolerances and yet is capable of trouble free
non-jamming operation in a dirty environment.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the present invention
will become better understood with regard to the following description,
appended claims, and accompanying drawings where:
FIG. 1 is a perspective view of the structural skeleton of the low
inclination push back storage rack system;
FIG. 2 is a side elevational view of the low inclination push back storage
rack system;
FIG. 3 is a fragmentary perspective view of the rear side of the front
horizontal support member of the rack of FIG. 2;
FIG. 3A is an enlarged fragmentary cross section of the rod and rod support
member of FIG. 3. FIG. 3B is an enlarged fragmentary cross section of the
rod and rod support member of FIG. 3 showing an alternative rod structure.
FIG. 4 is an exploded perspective view of the rods, rod supports, and
carriage assembly;
FIG. 5 is an enlarged fragmentary front elevational view of the low
inclination push back rack with a single carriage assembly;
FIG. 5a is an enlarged fragmentary front elevational view of the low
inclination push back rack with two nesting carriage assemblies;
FIG. 6 is an enlarged fragmentary front elevation of the carriage wheel
assembly;
FIG. 7 is an enlarged fragmentary front elevational view showing an
alternative scheme for mounting two carriages on an I beam.
DESCRIPTION
The low inclination push back storage rack system comprises of a framework
10, as best seen in FIGS. 1 and 2, having a plurality of horizontally and
vertically arranged storage lanes, each storage lane being deep enough to
accommodate a plurality of storage pallets 34, and a carriage transport
assembly 48, better seen in FIGS. 4, 5, and 6. The carriage transport
assembly 48 is installed in each storage lane for the purpose of
transporting pallets from the front loading and unloading position to a
rear storage position within each lane. The carriage transport assembly 48
also transports the pallets from the rear storage position to the front
loading and unloading position. The basic storage rack framework is a two
deep storage rack system as seen in FIGS. 1 and 2.
The framework of the system, best seen in FIG. 1, is comprised of vertical
columns supporting lateral horizontal framing members. At the front
loading end of the storage rack system, a plurality of front horizontal
support members 22 are fastened perpendicular to the front vertical
columns 20 thus forming the front of the storage array. The front face of
the storage rack system presents a plurality of horizontally and
vertically grouped storage lanes. Vertically grouped lanes are called a
storage bay. A multiplicity of horizontally grouped storage bays comprises
the storage array. Pallet loading and unloading is accomplished at the
front of each storage lane. The vertical columns are typically roll formed
channel members made of hot rolled steel but other structural forms and
materials would be suitable. The front horizontal support members 22 are
typically a channel shaped hot rolled steel as better seen in FIG. 3, but
other structural shapes could also be used. The front horizontal support
members 22 are attached to the front vertical columns 20 by removable and
detachable clamp means that are well known in the industry, however, any
type of rigid attachment means, permanent or otherwise could be employed.
The two deep framework of FIG. 1 shows rear horizontal support members 26
attached to the rear vertical columns 25 that are located at the rear of
the storage rack system. Similarly, middle vertical columns 23, located
between the rear and front columns, support the middle horizontal support
members 24. Although FIGS. 1 and 2 show a two deep system, the system can
be increased in depth by placing additional middle vertical columns and
middle horizontal support members between the front vertical columns 20
and the rear vertical columns 25. The middle and rear horizontal support
members can be structural channels similar to the front horizontal support
member 22, however roll formed channels and other structural shapes can
also be utilized.
As best seen in FIGS. 1 and 2, each storage lane is defined by the space
bounded, on its bottom, by its respective front, middle, and rear
horizontal support members 22, 24, and 26 and on its sides by its
respective front, middle, and rear vertical columns 20, 23, and 25. FIG. 2
illustrates a two deep storage lane that can accommodate two pallet loads,
a front pallet load positioned in the front loading position 32, and a
rear pallet load 33, stored at the rear storage position.
The base plane of each respective storage lane is defined by the upper
surfaces of the middle horizontal support members 24 and the rear
horizontal support members 26. The base plane is slightly angled or
inclined so as to be the greatest distance from the floor 36 at the rear
horizontal support member 26. The base plane is highest at the rear of
each storage lane and lowest at the front of each storage lane. The angle
or inclination of the base plane is desribed by the vertical distance
risen by the base plane between the front and rear of the storage lane
divided by the horizontal distance travelled between the front and rear of
the storage lane. This inclination or angle is described in inches per
foot. The inclination of the base plane is also known as the pitch and is
normally between 1/4 of an inch per foot to as much as 5/16 inch per foot.
An inclination of 1/4 inch per foot has been found to be suitable for
loads weighing between 200 and 3000 pounds. For lighter loads, the
inclination is increase to approximately 5/16 inch per foot.
The lower surfaces of the rod support members 30 rest directly on the
middle and rear horizontal support members 22, 24 and thus are directly on
the base plane. The front horizontal support member 22 is constructed of a
channel member, the material of which is usually hot rolled steel.
As best seen in FIG. 3, the front horizontal support member 22 is mounted
at a level so that the rod support members 30 intersect the front
horizontal support member 22 at a position that leaves sufficient space
for attachment of the front angles 40. As will be later described, the
front horizontal support member 22 also acts as a positive stop for the
front carriage member 52 making it necessary for the front angles 40 to be
mounted several inches below the upper flange of the front horizontal
support member 22. When carriage assembly 50 rolls forward, the front
carriage member 52 impacts against front horizontal support member 22
causing carriage assembly 50 to stop. The rod support members 30 are
supported at the front horizontal support members 22 by front angles 40
which are welded, bolted, or otherwise permanently attached to the rear
side of the front horizontal support member 22. The front angles 40
provide support for the rod support members 30, which are bolted, welded
or otherwise permanently attached to the front angles. Installing the
front horizontal support 22 channel with the open portion of the channel
toward the front of the storage rack and the wide flange vertically
aligned and positioned toward the inside of the storage lane allows easy
installation of the front angles 40.
To increase rigidity, the framework is equipped with suitably placed
diagonal struts 28. Diagonal struts 28 are fixedly attached to the front
vertical columns 20 and the middle vertical columns 23. Struts may also be
placed between middle vertical columns 23 and the rear vertical columns 25
or at any other locations providing the struts 28 do not interfere with
the passage of pallet loads within a storage lane.
Within each lane is mounted a pair of spaced apart rod support members 30
that extend from the front of the storage lane to the rear of the storage
lane. The rod support members 30 are mounted on the middle horizontal
support member 24 and rear horizontal support member 26. As previously
described, the bottom of the rod support members 30 intersect the vertical
webb of the front horizontal support member 22. Where the rod support
members 30 rest on middle horizontal support members 24 or the rear
horizontal support member 26, the rod support member is fastened with
carriage bolts 84 or other permanent means such as welding.
Rod support members 30 are made of a strong low cost material such as
simple hot rolled steel angle iron. Other types of structural members such
as channels or I beams may also be used. The most rearward end of the rod
support member 30 has a rear closure 44 welded at its end, as best seen in
FIG. 1 and FIG. 4. The purpose of the rear closure 44 is to close off the
rear end of the rod support member 30 and act as a positive stop to
prevent carriage assembly 50 from rolling out the rear of the storage
rack.
Elongated rounded rods 42 are positioned on the upper surfaces of the rod
support members 30 as best seen in FIG. 5. The elongated rounded rods 42
are mounted, one on each rod support member 30, parallel to one another
and spaced so as to receive the V groove wheels 72 of the carriage
assembly 50 as shown in FIG. 4. Rods 42 are tack welded to rod support
members 30, however other permanent fastening means may also be used. It
has been found that the most suitable elongated rounded rods 42 are simple
round rods made of cold rolled steel as shown in FIG. 3A. However, it also
is possible to use rods of any material or of any cross sectional shape
providing the shape has a round, oval, ellipsoid or otherwise generally
rounded surface which may be mounted facing in an upward direction. For
example, half round 42' is shown mounted on rod support member 30 in FIG.
3B. For example, the rods could have an oval cross section or be a half
oval or half rounded provided that the upper surface of the rods 42 that
contacts the wheels 72 has a round, oval, ellipsoid, or otherwise rounded
surface.
Carriage assemblies 50, as shown in FIG. 4, comprise a rectangular assembly
of front carriage member 52 and rear carriage member 54 joined by carriage
side members 56. The front carriage member defines the front end of the
carriage assembly and the rear carriage member defines the rear end of the
carriage assembly. The carriage members are angle members made of a
suitable material such as hot rolled steel, however other forms such as
channels or bar stock and materials such as cold rolled steel or aluminum
may also be suitable. The carriage assemblies 50 are fastened together in
some permanent fashion, typically welding, thus forming a rectangular
assembly. As best seen in FIG. 5, the carriage side members 56, or side
rails as they can also be referred to, have the flat horizontal flange
extending toward the outside of the carriage assembly. The flat upper
surface of the carriage assembly defines a pallet receiving surface 58. In
some instances, it may be desirable to add reinforcing members 66, FIG. 4,
to the center of the carriage assembly 50. The reinforcing members 66 may
be angled members with a flat flange disposed on the pallet receiving
surface 58. The reinforcing members 66 strengthen the carriage assemby 50
and provide better support for the pallet load 33.
As best seen in FIG. 6, holes are drilled in the carriage side members 56
to permit shoulder bolts 70 to be mounted on the side members 56. Wheel
assemblies 71 are rotationally mounted on shoulder bolts 70. Of course,
shoulder bolts 70 are merely axles on which the wheel assemblies 71
rotate. Any axle means that would rotatably support wheel assembly 71
would suffice. The wheel assemblies 71 are comprised of a grooved wheel
72, an inner bearing 80 mounted within the bore of the wheel 72, and plugs
82 mounted in recesses at either side of the wheel 72. Wheel 72 is
preferably a V groove type wheel but other groove shapes, such as circular
or oval, or other notch shapes may be found satisfactory. The plugs 82 are
washer shaped, having an inside diameter sufficiently large to allow the
shoulder bolt 70 to pass and an outside diameter larger than that of the
inner bearing 80. The plugs 82 trap the inner bearing 80 within the wheel
72.
The wheel assemblies 71 are mounted on shoulder bolts 70 by disposing the
wheel assemblies 71 between washers 74. The inside diameter of washers 74
is large enough to allow clear passage of shoulder bolt 70. As best seen
in FIG. 6, shoulder bolt 70 is positioned so that its shoulder is disposed
against carriage side member 56. When shoulder bolt 70 is tightened with
nut 76 there are lateral clearances 77 and 77' that allow wheel 72 to
rotate freely. The sum of clearances 77 and 77' approximates one quarter
of an inch. The clearances allow the wheel assemblies 71 to drift back and
forth along the length of the shoulder of shoulder bolt 70. The drifting
movement of the wheel assemblies 71 compensates for inaccuracies in
parallelism between rods 42. In order to prevent the shoulder bolts 70
from loosening during carriage movement, the shoulder bolts are equipped
with lock washer 78 and nut 76. Socket head shoulder bolts have been found
to be the most convenient to use. Hex head shoulder bolts or other types
could also be utilized. It is also possible to substitute self locking
nuts for the lock washer and nut arrangement previously described. Wheels
72 are mounted on the carriage side members 56 so that the V grooves of
the wheels 72 on each side member 56 are in alignment and roll on the same
rod 42. As shown in FIG. 5, the V groove wheels 72 on each side member 56
are supported by rods 42 resting on the rod support members 30. Minor
differences in wheel spacing is compensated for by the previously
described wheel drift.
Each V groove wheel 72 contacts its respective mating rod 42 at two points.
Moreover, contact between wheel 72 and rod 42 are at a position
sufficiently above the rod support member 30 that no debris collects on
the rod. With no debris to interfere with wheel movement and with the low
friction caused by the two point contact between the V groove wheel 72 and
rod 42, the pitch or inclination of the rod support members 30 and rods 42
is minimized. A pitch of 1/4 inch per foot has been found sufficient for
pallet loads weighting between 200 and 1500 pounds. Very lightly loaded
carriages may require an inclination of up to 5/16 inch per foot. Velocity
of the carriage assembly 50 in rolling forward is low and shock absorbing
means to cushion the impact of the carriages 50 against the front
horizontal support member 22 is unnecessary. In this system, the carriages
are stopped by front carriage member 52 contacting front horizontal
support member 22.
A major benefit of this low inclination push back storage rack system is
that it consumes less overhead space than systems which utilize flanged
wheel or flat wheel rail systems. Flanged and flat wheel rail systems need
greater inclination to compensate for debris build up and higher
frictional losses caused by the large contact area between the wheel and
rails. The low inclination directly translates to lowering the overhead
requirements of a given depth system.
If a given storage lane is empty, carriage 50 is in the front loading
position having previously returned to that position under the force of
gravity. A first pallet load is placed on the carriage. A second pallet
load is lifted, typically by a forklift, and moved to a position adjacent
to the first pallet load at the mouth of the storage lane. The second
pallet load is now pushed against the first pallet load, pushing the first
pallet load and the carriage assembly upon which it rests to the rear
storage position. At this point the first pallet load is rear pallet load
33, as shown in FIG. 2, and the pallet on which it is supported is rear
pallet 34.
The forklift then lowers the second pallet load. The second pallet load is
front pallet load 32 which is resting on front pallet 35. Front pallet 35
is supported by the rod support members and rods in the front storage
location.
Unloading the pallets is begun by a forklift elevating front pallet 35 and
withdrawing it from the push back rack. As this withdrawal is
accomplished, the carriage 50 supporting the rear pallet load 33 in the
rear storage position rolls, under the force of gravity, to the front
storage position is available for removal.
This invention contemplates additional middle vertical columns 23 and
middle horizontal support members 24 being placed between the front and
rear of the storage lane to increase the depth of the storage lane.
Increasing the depth of the lane allows three pallet loads to be stored in
the lane. However, when three pallet loads are stored, carriage assemblies
must be provided to transport two of the pallet loads in a rearward
direction.
The number of carriages may be increased by mounting a plurality of rod
support members 30 in each storage lane as shown in FIGS. 5a and 7. FIG.
5a shows a second pair of rod support members 30' and rods 42' mounted
directly on the vertical columns. Such attachment is by bolting, welding,
or otherwise permanently affixing the vertical flange of rod support
members 30' to the vertical columns. Rod support members 30' are placed
high enough on the vertical columns so there is sufficient clearance for
the pallet receiving surface 58 of the lower carriage assembly 48 to pass
under the upper carriage assembly 48'.
An alternative scheme for mounting carriages that pass one beneath the
other is shown in FIG. 7. Here the rod support member 30 is beam 88 which
may be an I beam. Rod 42a is welded or otherwise permanently attached to
the upper surface of the lower outer flange 90. Rod 42b is welded or
otherwise permanently attached to the upper surface of the lower inner
flange 92. Upper carriage assembly 50a is modified to include extension
member 62 to which shoulder bolt 70a is bolted. Extension member 62
provides the vertical clearance necessary for upper carriage assembly 50a
to clear the upper flange of the beam 88 and lower carriage assembly 50b.
In configurations utilizing two carriage assemblies, the carriages
originally nest in the first storage location of the storage lane. The
first palletized load is placed on the uppermost carriage. A second
subsequently positioned palletized load pushes the uppermost carriage
rearwardly and the second load is placed on the lower carriage. A third
palletized load is then pushed against the second load thus moving both
the first and second loads and their supporting carriages rearwardly. The
third load is then placed directly on the rods and rod support members.
Load removal is a simple reversal of the process.
It should be understood that the above described preferred embodiment of
the invention is not intended to limit the scope of the invention and that
changes and modifications can be made to the described embodiment without
departing from the spirit and scope of the appended claims.
Top